Sequence Flashing Lights (SFL) : A line of very high intensity lights centered on a runway approach course flashing in rapid sequence to show direction; provides pilot with a "tracer bullet" effect
Ilan Kelman (ed.), Vulnerability and Resilience Definitions and References, Version 2, 2007. http://www.islandvulnerability.org/docs/vulnres.pd f, (Vulnr and Resilience - Brit) {524}